Role of putrescine in regulation of the sigmaS subunit of RNA polymerase in Escherichia coli cells on transition to stationary phase.

Expression of the rpoS gene encoding the sigmaS subunit of E. coli RNA polymerase was studied on transition to the stationary phase and under conditions of starvation. Polyamines, in particular putrescine, are involved in regulation of the rpoS expression by concentration-dependent stimulation at the levels of translation and stability of the protein sigmaS. The stimulatory effect of exogenous putrescine inversely depended on its content in the cell and was the most pronounced in the beginning of the exponential growth. Possible mechanisms of the polyamine effect on the rpoS expression on post-transcriptional and post-translational levels are discussed. Copyright 2004 MAIK